1. Field of the Invention
The invention relates to a device for collecting solar energy and transferring it to a reception body to be heated.
2. Description of the Related Art
It has long been sought to collect solar energy for heating a reception body such as, for example, an outer wall of a building or a volume of air inside a building.
This energy recuperation is of interest in particular for providing, during cold weather, supplementary heat energy to reception bodies forming part of buildings or other structures exposed to solar radiation, even of low intensity.
For this purpose, various means are known, such as for example black- or dark-coloured coatings which are applied onto the reception surfaces exposed to the solar radiation. These coatings, which function according to the black body principle, have the advantage of providing high solar reception and recuperation throughout the entire period when they are exposed to the solar radiation.
However, as soon as this radiation ceases, in particular when the sun has gone down, these known coatings give out, because of heat losses, a large portion of the heat energy which they have previously collected and stored. Such coatings actually have a loss coefficient which is generally of the order of 6 to 8 W/.degree.C./m.sup.2.
Since these losses are proportional to the difference between the temperature reached by the coating and the temperature of the ambient outer medium, the heat release is commensurately higher as this difference is greater.
Furthermore, solar energy recuperation devices are known which are also called "transparent insulations", and which comprise transparent walls, of glass or plastic, which extend in directions parallel or perpendicular to the reception surfaces to be heated.
These transparent insulations are intended to allow the solar radiation to pass and to store the heat energy.
A typical example of these devices is that of greenhouses used in horticulture.
These devices of the type with transparent insulation may be combined, as appropriate, with dark-coloured coatings such as indicated above. They themselves also have the drawback of having high heat losses when they are no longer exposed to the solar radiation.
Furthermore, the known devices mentioned hereinabove above also have the drawback of continuously collecting solar energy, in particular in hot weather, that is to say at a time when, for certain applications, the recuperation of this energy is not desired, and is even deleterious.
It is then necessary to provide means for making these devices inoperative when the user so desires.